Commander

A good commander is a fierce leader, someone who inspires greatness in others by comitting great deeds in battle. Their mere presence is magnetic, it's enough to cause bandits and monsters to seek easier prey. They lead in the battlefield through deeds, not words, inspiring courage and conviction, they are the horn that calls to allies in times of need, A banneret prefers to lead through deeds, not words.

A lone commander is a skilled warrior on its own, but a commander leading a band of allies can transform even the most poorly equipped militia into a ferocious war band, as they are often found as the leaders of their parties, as captains of ships, as lieutenants leading armies to victories.

Diplomatic Envoy

Beginning when you first choose this archetype at 3rd level, you gain proficiency with the Persuasion if you don't have it already. Your proficiency bonus is doubled for any ability check you make that uses Persuasion, and you learn two languages of your choice.

Commander's Aid

Also at 3rd level, you help your allies whenever needed, but specially on the battlefield, as you lead them in their attacks towards victory. You can take the Help action as a bonus action. 

If you aid your ally in a attacking a creature in this manner, the creature can be at any distance instead of only within 5 feet of you, as long as you hit that creature with a weapon attack this turn. If that attack hits, it deals an additional 1d4 damage.

Rallying Surge

At 7th level, you can, as a bonus action, inspire your allies to fight past their injuries.

Creatures of your choice that can see or hear you, other than you and within 60 feet of you, up to a number equal to your proficiency bonus, gain temporary hit points equal to 1d6 + your fighter level. In addition, choose one hostile creature within 60 feet of you. It must succeed on a Charisma saving throw (DC= 8 + your proficiency bonus + your Charisma modifier) or become frightened until the end of your next turn.

You can use this feature twice, regaining the ability to use it again when you finish long rest, or you can use it without expending a use when you use your Second Wind feature (no action required).

Inspiring Charge

Starting at 10th level, when you use your Action Surge feature, you can choose an allied creature within 60 feet of you. It gains temporary hit points equal to your fighter level, and on its next turn, it gains an additional action. That action can be used only to take the Attack (one attack only), Dash, Disengage or [Tooltip Not Found] actions.

Bulwark of Leadership

When you reach 15th level, you can command even in times when your allies don't succeed. Whenever an allied creature within 60 feet of you fails a saving throw or is reduced to zero hit points, you may perform one of the following:

• Make a single weapon attack.
• Use your reaction to have them succeed on the failed saving throw.
• Gain temporary hit points equal to half your fighter level + your Charisma modifier.

You can use this feature once, regaining the ability to use it again when you finish a long rest, or if you expend a use of Indomitable to use it again.

Fight as One

By the time you've reached 18th level, you can tap into the connection in between your allies and yourself to bolster everyone's capabilities. As an action, choose any number of allies within 30 feet of you. Upon activating this feature, you can restore a number of hit points equal to four times your fighter level, divided as you choose amongst those allies; and you regain a use of your Action Surge, Indomitable and Second Wind features. 

Additionally, for the next minute, the chosen creatures gain the following benefits:

• A +1 to their AC.
• A bonus to their saving throws equal to half your proficiency bonus.
• Advantage on saving throws against being charmed or frightened.

The effects end for a particular creature if they are ever more than 30 feet away from any of the other affected creatures, or if you are  incapacitated. You can use this feature once, gaining the ability to use it again when you finish a long rest.